Machine and method for producing gears



Feb. 2, 1954 STEWART ET AL 2,667,818

MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet 2 Inwcntor ARTHUR- L STEWART EONARD O. CARLSEN 1954 A. L. STEWART ET AL 2,667,818

MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet 1 FIG.

3nnentor ARTHUR L. STEWART LEONARD O. CARLS EN Wmtoweg Feb. 2, 1954 Filed Oct.

A. L. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS 14 Sheets-Sheet 5 FIG. 3

V 'Jmneutor ARTHUR L. STEWART B LEONARD O. CARLSEN Gttorneg Feb. 2, 1954 A. STEWART ET AL 2,667,818

MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 E&

14 Sheets-Sheet 4 Zhwentor ARTHUR L. STEWART LEONARD 0. CA RLSEN Gttorneg Feb. 2, 1954 A. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS 14 Sheets-Sheet 5 Filed Oct. 15, 1947 Enneutor ARTHUR L. STEWART LEONARD O. CARLSEN Feb. 2, 1954 A. L. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS 14 Sheets-She 6 Filed Oct. 15, 1947 Summer ARTHUR L. STEWART E LEONARD O. CARLSEN u WM . f mtomeg A. L. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS Feb. 2, 1954 14 Sheets-Sheet 7 Filed Oct. 15, 1947 Feb. 2, 1954 A. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS 14 Sheets-Sheet 8 Filed Oct. 15, 1947 8m Q 67. m 8m Nwm Q8 Q 9w 9w 4 mom Cw J mmm ow 6m E Ri 6N .wvm n k 0mm Gm A.WQN @WN nqm mwm oqm QQN 3 v qmm nmm mmm mmm .mm I nmm Sum Ifimwntox ARTHUR L STEWART LEONARD G. CARLSEN 1954 A. L. STEWART ET AL 2,667,818

MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet 9 I I I87 FIG. I8

\ y Ihwcntor I I 1 ARTHUR L. STEWART A 1 B LEONARD o. CARLSEN I B 1 I89 I 185 1954 A. STEWART ET AL 1 MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet 1O FIG. 17

425 4 Summer 32' ARTHUR L. STEWART 8g LEONARD O. CAR LSEN f mforueg A. L. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS Feb. 2, 1954 14 Sheets-Sheet 11 Filed Oct. 15, 1947 FIG. 59

SnDentor ARTHUR L. STEWART a LEONARD O. CARLSEN 4 attorneg Feb. 2, 1954 A. 1.. STEWART ET AL 2,667,818

MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet 12 Summer ARTHUR L. STEWART LEONARD O. CARLSEN Gttorneg fieb. 2, 1954 A. L. STEWART ET AL MACHINE AND METHOD FOR PRODUCING GEARS l4 Sheets-Sheet 13 Filed Oct. 15, 1947 FIG. 22

FIG. 2!

F E a 4 3nveutor ARTHUR L. STEWART u LEONARD O. CARLSEN Gttornegl Feb, 1954 A. L. STEWART ET AL 7 8 MACHINE AND METHOD FOR PRODUCING GEARS Filed Oct. 15, 1947 14 Sheets-Sheet l4 Znmcntor ARTHUR L. STEWART LEONARD O. CARLSEN Patented Feb. 2, 1954 UNITED STAES.

PATENT OFFICE MACHFNE AND METHOD FOR. PRODUCING- GEARS York Application October 15', 1947, Serial No. 779,890

24 Claims.

The present invention relates to machines for producing gears and particularly to machines for generating longitudinally-curved tooth gears, such as spiral bevel and hypoid gears, in an il'l' termittent indexing operation.

In machines of the intermittent indexing type for generating gears, a cycle of operation comprises feed of tool and Work into engagement, roll of tool and work relative to one another to generate a tooth side or sides, withdrawal of the work from engagement with the tool, and indexing of the work. The cycle is repeated for each tooth until the operation on the gear is completed. In a bevel or bypoid gear generator, the rolling motion may be achieved by rocking-a cradle, on which either the tool or the work is mounted, and simultaneously, and in time therewith, rotating the work on its axis. Thereby the Work is rolled relative to the tool as though it were meshingwith a gear of which the tool represents a tooth. Generation may take place during both forward and return movements of the cradle and the work may be indexed at the end of the return roll, or generation may take place during roll in one direction only, and the Work may be disengaged from the tool and indexed during the return roll.

Conventional bevel and hypoid gear generators, which operate according to the intermittent indexing principle, are made in two types, namely segment-roll and geared-roll. In segmentroll machines, a. gear segment, which is connected to the work, meshes with a gear segment that has a fixed relation to the tool, and oscillation of the cradle causes one segment to roll on the other to impart the required rotation to the Work in time with the cradle movement. The cradle may be oscillated by a cam or eccentric. In geared-roll machines, both the cradle and the work spindle are driven by trains of gearing which include change gears for timing their relative motions, and a reversing mechanism is pro vided which periodically reverses these trains of gearing to cause oscillation of the cradle and the required rotation of the work.

Segment-roll machines are relatively simple in construction because reversal is effected by the cam or eccentric, which rotates continuously in one direction, and because the timing of the motions of tool and work are effected directly through the two segments. Segment-roll machines are, however, more or less special purpose machines, because for each difierent gear that is to be produced, ordinarily at least a difierent work segment is required. The number and cost or the segments required to cover the full range of the machine make machines of this type, therefore, unsuitable-for general purpose use.

Geared-r011 machines have the advantage that the ratio of roll between tool and work can be varied for different jobs simply by substitution of change gears, which are relatively inexpensive. In conventional geared-roll machines, however, reversing mechanism is required, as above stated; and a reversing mechanism is a complicated device, dii licult totime and expensive to construct if it is to operate quietly.

In geared-roll machines of the most universal type for generating spiral bevel and hypoid gears in which a face-mill cutter or annular grinding wheel is employed as a tool, there are two angular adjustments provided for the cutter aside from the adjustments required for spiral angle of the gear to be produced. These two angular adjustments permit of general control of the tooth bearing of the gear to be produced, enable a gear to be generated conjugate to a mate form-cut gear aswell as to a crown gear or other basic gear, and permit of using a single cutter to cut gears of different pressure angles. I-leretofore for at least one of these adjustments tilt about a pivot has been required. Thus the problem of clamping the cutter rigidly in its tilted position is presented.

In conventional spiral bevel and hypoid gear generating machines of the geared-roll type, tool and Work are rolledv together at a uniform rateduring generation. This is true even though.

the ratio of roll may be varied duringgeneration. Spiral bevel and hypoid gearsicuton conventional gearechroll machines, therefore, have flats or generating cuts that are unequally spaced along the lengths of their tooth surfaces. The flats are closer together at the inner or small end of the tooth than at the outer or large end of the tooth. This means that the tooth surface finish on a gear generated on a conventional machine is not as goodat the. large end of the tooth as 3 driven by gear trains that include change gears but in which oscillation of the cradle is achieved without use of a reversing mechanism.

Another object of the invention is to provide a universal type machine for generating longitudinally curved tooth bevel and hypoid gears in which the cutter mounting and drive will be much more rigid than in prior type machines.

A further object of the invention is to provide a machine of the character described on which the cutter can be adjusted angularly to represent a form-cut tapered gear as well as a basic crown gear and on which the cutter can also be adjusted angularly to cut gears of diiferent pressure angles, and in which both of these adjustments are attained without pivotal movement.

Another object of the invention is to provide a gear cutting machine in which the cutter mounting will be relatively simple and compact despite the number and range of cutter adjustments required.

A still further object of the invention is to provide a spiral bevel and hypoid gear generating machine in which work and cradle can be driven through gear trains including change gears but in which the rate of roll can be varied to secure speeding-up and slowing-down of the roll at different points along the length of a tooth as may be desired.

Still another object of the invention is to provide a spiral bevel and hypoid gear generating machine of the character described on which generating cuts of uniform width can be produced all along the length of a tooth surface so that the same tooth surface finish can be attained at the large end of a tooth as at the small end.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In a machine constructed according to the preferred embodiment of the present invention, the generating motion of the machine is controlled by a barrel cam which drives the cradle and the work spindle through a segment and separate trains of gearing, each of which includes change gears. [he use of the cam obviates the need for a reversing mechanism and simplifies the whole structure of the machine. Moreover, by suitably shaping the cam track, variation in the rate of roll can be attained. Through use of different ratio of roll change gears for different jobs, this variation in rate of roll can be suitably applied in the cutting of diiferent gears. Through use of a cam having a track formed to produce suitable variation in the rate of roll, also. uniform widths of generating cuts all along the length of a tooth surface of a longitudinally curved tooth bevel or hypoid gear can be secured where desired.

In a spiral bevel or hypoid gear generating machine constructed according to the present invention, the tool spindle is journaled in a carrier which is adjustable in a swivel head through an angle of 360 about an axis inclined to the axis of the tool spindle. This swivel head in turn is mounted eccentrically in an eccentric drum for adjustment through an angle of 360 about an axis parallel to but offset from the axis of the drum. The drum is in turn mounted eccentrically in the cradle and is adjustable therein through an angle of 360 about an axis parallel to but offset from the axis of the cradle. The cradle is not only oscillatable in the base of the machine but is mounted therein to be adjustable through an angle of 360. Angular adjustment of the drum in the cradle varies the radial position of the tool from the axis of the cradle and adjustment of the cradle on the base of the machine enables the position of the tool to be varied about the axis of the cradle. Thus, the tool may be positioned to cut gears of any desired spiral angle. The angular adjustments of the swivel head and carrier enable a tool to be positioned to represent any tapered gear or basic gear during generation of the work and permit use of a cutter to cut gears of different pressure angles. The whole structure is very compact and rigid.

In the drawings:

Fig. l is a side elevation of a machine built according to one embodiment of this invention, the cover plate at one side of the machine being removed better to show certain operating parts;

Fig. 2 is a plan view of the machine with parts broken away;

Fig. 3 is a vertical sectional view through the machine looking at the face of the cutter carrying cradle;

Fig. 4 is a fragmentary longitudinal sectional view through the cutter carrying cradle, showing the cutter mounting and cutter drive;

Fig. 5 is a side elevational view of one of the brackets on the cradle housing, showing parts of the generating and feed mechanisms, parts being broken away;

Fig. 6 is a rear view of the same bracket, parts being broken away;

Fig. 7 is a view looking at the front of these brackets, showing details of the drives to the control cam and to the indexing mechanism of the machine;

Fig. 8 is a similar view, but with parts of the drive to the index mechanism removed in order to show more clearly details of the index mechanism itself;

Fig. 9 is a diametrical sectional view through the drive member of the modified Geneva type index mechanism of the machine;

Fig. 10 is a View showing the trip cam and trip lever of the indexing mechanism;

Figs. 11 and 12 are views at right angles to one another showing in detail the trip and lock-up levers of the index mechanism;

Fig. 13 is a horizontal sectional view taken on the line i3-i3 of Fig. 8;

Fig. 14 is a fragmentary sectional View showing details of the drive to the cradle;

Fig. 15 is a fragmentary sectional View, showing details of the feed mechanism of the machine;

Fig. 16 is a sectional view showing details of the mechanism for moving the work between loading and operative positions, this view being taken at right angles to the View of Fig. 15;

Fig. 17 is a transverse vertical sectional view through the work head of the machine;

Fig. 18 is a longitudinal vertical sectional View through the work head, but on a somewhat smaller scale than Fig. 16;

Fig. 19 is a drive diagram of the machine as built according to one embodiment of the invention;

Fig. 20 is a fragmentary drive diagram of a modified form of machine;

Figs. 21 and 22 are diagrammatic views showing different positions to which the cutter may be adjusted by the adjustments of the present machine;

Fig. 23 is a diagrammatic view showing how, when the cutter is adjusted into one position, it may represent a nominal crown gear, that is, a generating gear having a face angle of Fig. 24' is a diagrammatic view showing'how in another position the cutter may represent a tooth of a generating gear Whose pitchcone angle is considerably less than 99;

Fig. 25 is a diagrammatic view takenat right angles to the views of Figs. 23 and 24, showing one position of the cutter when the gear, which itrepresents, has teeth of positive spiral angle;

Fig. 26 is a diagrammatic View showing how a cutter with a given blade pressure angle may beadjusted in the machine of the present invention to have different effective cutting pressure'angles;

Fig. 27 is a diagrammatic view showing the po-' sitions of a cutter and pinion blank at the beginning end of the roll in generating a spiral bevel or hypoid pinion;

Figs. 28 and 29 are a section taken lengthwise of the tooth space of a longitudinally curved tooth gear or pinion and a fragmentary perspective view of this tooth space, respectively, further illustrating why corresponding parts of the tooth profile are not cut simultaneously along the whole length of a tooth space;

Fig. 30 is a fragmentary view of a spiral bevel pinion such as might be generated on conventional machines, showing the nature of the cuts talzen along height of the tooth profile from one end of the tooth to the other; and

31 is a corresponding View showing how these profile cuts may be equi-spaced by use of the machine of the present invention.

Referring now to the drawingsby numerals of reference, denotes the base of the machine. lecured to the base at one end thereof is the cradle housing 3i (Fig. 3). Mounted on the base at the other end thereof for angular adjustment thereon is sub-base 32 (Fig. 2). Journaled in the housing 3! on anti-friction bearings 33 and 3 3 is a cradle shown fragm-entarily only in Fig. 4.

Mounted in the cradle on plain bearings 4i and 32 for rotatable adjustment therein through an angle of 360 about an axis eccentric to the axis of the cradle is a drum so. Journaled in the drum on plain bearings it and M for rotatable adjustment therein through an angle of 360 about an axis eccentric to the axis of the drum is a swivel head 45. Journaled in the swivel head 45 on plain bearings 5i and 52 for rotatable adjustment therein about an angularly inclined to the axis of the swivel head is a carrier 50. Journaled in the carrier on anti-friction bearings 56 and 5'! is the cutter spindle 55.

The face mill cutter C, which is adapted to be used on the machine, may be secured to the cutter spindle es in any suitable manner as by means of a central bolt @i which threads into the spindle 55. The cutter shown is of the type disclosed in U. S. Patent No. 2,586,428,. granted February 19, 1952, and has a truing disc 62' (Fig. 4)

secured to its rear face as by means of screws 63 r (Fig. 3). Its cutting blades are denoted at 66.

The cutter spindle 55 is rotated continuously during operation of the machine, being driven from a motor lii (Figs. 6 and 19) which is mounted at a suitable point in the cradle housing 3!. The armature shaft of this motor is connected to a shaft "H which is journaled in the cradle housing 3i and which carries a bevel pinion i2 that meshes with and drives a bevel gear i3. This gear is mounted on a shaft 14 to which is secured a spur gear it. This shaft is also journaled in the cradle housing 3 l.

The spur gear meshes with and drives a spur gear it which is secured to a shaft 17. There 6 is a spur pinion 78 secured to this shaft which meshes with and drives a spur gear it. The gear 19 is secured to ashaft at to which is secured a spur gear'i? I. Shafts l! and iib are journaled in cradle housing 3|. The gear 8i meshes with and drives a spur gear 82' (Figs. 19 and i) which is keyed" or otherwise secured to a shaft 5% that is journaled on anti-friction bearings 65 and 86 in a sleeve 87'. This sleeve is journale'd in a bracket 88 that is secured by screws 8% to the cradle 35-. It is secured by screws 9 to a bearing Si that is journaled in cradle housing 3|.

The shaft 538 is co-axial with the cradle 35. Keyed tothe shaft t l at its inner end is a spur pinion 55 which meshes with and drives a spur gear 95. This gear is integral with a shaft 9-! that is j'ournaled on anti-friction bearings 98- and 99- in a bracket 583 which secured by screws Iii i to the cradle.

Theshaft a? is mounted coaxial with the drum Mi. It'has a spur pinion Hi5 keyed to its inner end which meshes with a spur gear liit which is keyed to the outer end of a shaft 59?. This shaft is journaled on anti-friction bearings E? and IE9 in swivel head at. Integral with this shaft at its inner end is an angular bevel gear I H This gear meshes with an angular bevel gear H5 which is keyed to a sleeve H6 that is journaleo. on anti-friction bearings iii and I 58 on a stud I29.

This stud is held against axial movement relative to swivel head it" by a nut 52! which threads onto the stud. Integral with the sieeve lid is a spur gear E25. This meshes with a spur gear fit that is integral with a shaft I27 which is journaled on anti-friction bearings lit and 52% in a sleeve I 35. The sleeve lii i is secured in any suitable manner to the carrier There is a bevel gear E35 keyed to the inner end of shaft [21. This meshes with a bevel gear E35 which is keyed to a shaft it'l. This shaft is journale'd on anti-friction bearings its and I39 in the carrier 55 with its axis at right angles to the axis of the cutter spindle 5c. Integral with this shaft it? at its inner end is a bevel pinion M9 which meshes with and drives a bevel gear l-i-f that is secured by screws M2 to the cutter spindle 55 to be coaxial with the cutter spindle.

The stud l2il is coaxial with the carrier 50 and the axis of the carrier is inclined to and intersects both the axis of swivel head 65 and the axis of cutter spindle 55. When supporting ring 5c is adjusted angularly, then, the axis of cutter spindle 5'5- swings about stud I29 and traces a conical surface about the axis of this stud. In this adjustment gear 826 rolls on gear I25 and the axis of the cutter spindle rolls about the apex of this conical surface.

The cradle 35" is adapted to be swung first in one direction and then in the other. The cutter may cut during swing of the cradle in one direction only or during swing of the cradle in opposite directions, according to any of the well known generating methods.

The swinging movement of the cradle is effected by operation of a barrel cam 85d (Figs. 5, 6, and 19). This cam has a plurality of tracks l5l, I52, and IE3. It is keyed to a shaft that is journaled on anti-friction bearings E563 and 57 in a bracket r58 that is secured in any suitable manner to the cradle housing 3 i. The tracks I51 and 552 control the movement of the work to and from operative engagement with the tool as will be described later. The track I53 controls the operation of the cradle.

A tapered cam roller I'60 engages in this track I53. It is mounted by means of anti-friction bearings I6I on a stud I62 which is secured by screws I 63 to a rocker arm I 85. The rocker arm is journaled at its lower end by means of antifriction bearings I68 on a stud I61 which is secured by screws I 08 to the bracket I58, The stud projects through an arcuate slot I69 in cam housing I84 so that roller I80 may engage in cam track I533. The slot I69 is concentric with pivot pin I61.

There is a spur gear segment I secured b screws I1I to the outer end of rocker arm I65. This spur gear segment meshes with a spur gear I which is secured to a shaft I16 that is journaled in bracket I58. The pinion I15 meshes with a spur gear I18 that is secured to a shaft I19. There is a second spur gear I88 secured to this shaft. This gear may be meshed with a spur gear I8I that is secured to a shaft I82, or it may be meshed with a spur gear I83 that is secured to shaft I84. This shaft has a second spur gear I85 secured to it which meshes with a spur gear I86 that is secured to shaft I82. Shaft I82 is journaled on anti-friction bearings I81 and I89 (Fig. 14) in bracket I58 and has a hypoid pinion I88 integral with it at its inner end. This hypoid pinion meshes with a hypoid gear I90 which is secured by bolts I9I (Fig. 4) to the cradle 35 and which is coaxial with cradle 35.

The segmental gear I10 (Fig. 6) is held against an arcuate guide surface I12 (Fig. 5) by a gib I13 which is secured to cam housing I64 by screws I14, so as to prevent chatter of the rocker arm I65 in its movement. Guide surface I12 is curved about the axis of stud I61.

The cam I50 makes one revolution per tooth of the work as will be described hereinafter more particularly, and the cam track I53 will operate through the gearing described, therefore, to swing the cradle forward and back once per tooth of the work. Whether the cradle swings upward and then downward in a throat-cutting cycle, or, vice-versa, downward and then upward is determined by whether shaft I82 is driven through gears I80 and I8I or through gears'l80, I83, I85, and I88. When shaft I82 is to be driven through gears I80 and I8I, change gear I83 may be removed from the machine, and when shaft I82 is to be driven in the opposite direction, change gear I8I may be removed.

Shaft I82 may be rotated manually to adjust cradle 35 angularly about its axis. Drum 40 may be adjusted angularly on its axis by rotation of a stub shaft I92 (Fig. 3) which is journaled in the cradle 35 and which carries a spur pinion (not shown) that meshes with a spur gear I93 (Fig. 4) which is secured to drum 40. Swivel head 45 is adjusted angularly in drum 40 by rotation of stub shaft I94 (Fig. 3) which carries a spur pinion (not shown) that meshes with a spur gear I99 (Fig. 4) that is secured by screws 202 to swivel head 45. Carrier 50 may be adjusted angularly in swivel head 45 by rotation of stub shaft 201 (Figs. 3 and 4) which carries a spur pinion 208 that meshes with a spur gear 209 which is secured to carrier 50.

A ring or gib 2 I1, that is secured by screws 2 I8 to cradle housing 3!, serves to hold the cradle against forward movement axially in the cradle housing. This gib is graduated as shown in Fig. 3 to read against a vernier 2I1' to permit of the angular adjustment of the cradle being made accurately. The vernier is fastened to the cradle. A graduated ring 2 I9, that is secured to cradle 35 and that reads against a vernier 2I9' which is fastened, to drum 40, serves for accurate adjustment of drum 40 in the cradle. A ring or gib 22I (Figs. 3 and 4), that is secured by screws 221 to drum 40, serves to hold swivel head against movement in one direction axially in the drum. This gib is graduated to read against a vernier 22 I which is secured to the swivel head, to permit accurate adjustment of the swivel head in the drum. A ring or gib 229, that is secured to swivel head 45, serves to prevent axial movement of carrier in swivel head 45. This gib is graduated to read against a vernier 229', which is secured to carrier 50, to permit accurate adjustment of the supporting ring in the swivel head. A gib 238, which is secured by screws 231 (Fig. 4) to carrier 50, serves to secure cutter spindle in place.

With the shaft 84 mounted coaxial with the cradle, the shaft 91 mounted coaxial with the drum 40, the shaft I91 mounted coaxial with the swivel head 45, and the shaft I28 mounted coaxial with the carrier 50, the drive can be transmitted to the cutter in any position of its adjustment without use of telescoping shafts. Thus the greatest accuracy with freedom from excessive backlash in the drive train is achieved, The front face of the cradle, and the front face of drum 40 are parallel and perpendicular to the axes of these two parts. The front face of swivel head 45 is approximately helical so as to accommodate the carrier 58 whose axis is inclined to the axis of the swivel head. The front face of the supporting ring is perpendicular to the axis of the cutter spindle 55 as shown in Fig. 4.-

The barrel cam I50 is adapted to be driven from shaft 14 (Fig. 19). There is a spur gear I95 secured to this shaft which meshes with a spur gear I98. Gear I96 is secured to a shaft I91 which carries a spur gear I98 that meshes with a spur gear 200. Gear 200 is secured to a shaft 20L A spur gear 203, which is secured to this shaft, meshes with a spur gear 205 that is keyed to a shaft 280. There is a bevel miter gear 2I0 (Figs. '7, 8 and 19) fastened to shaft 208 which meshes with a bevel miter gear 2I I. The latter miter gear is secured to a shaft 2I2 which is journaled on anti-friction bearings 20!) and 2I4 in a bracket 389 which is secured to cradle housing 3 I. A hypoid pinion 2 I 3 is integral with shaft 2I2 at its lower end. This pinion meshes with a hypoid gear 2i 5 that is secured to one end of the barrel cam by screws 2% (Fig. 5). The gearing is so selected that the cam I58 makes one revolution per cycle of the machine, that is, one revolution per tooth side or sides.

During generation of the tooth side or tooth sides, the Work is driven in time with the cradle.

The generating drive to the work is derived from shaft !82 (Figs. 14 and 19). This shaft'has a bevel gear 220 keyed to it which meshes with and drives a bevel pinion 22I. This bevel pinion is keyed to a shaft 222 which is journaled on anti-friction bearings 223 and 224 in the bracket I58. There is a spur gear 225 keyed to the shaft 222 at its outer end. This gear meshes with a spur gear 228. This gear is secured to a stud shaft 221 which is journaled in a quadrant 228 (Fig. 5). The quadrant may be of conventional construction and is adapted to swing about stud 229 and to be secured in any adjusted position by bolt 236. Stub shaft 221 carries at its outer end a spur gear 230. Gear 238 meshes with a spur gear 23I which is secured to a shaft 232 (Figs. 13 and 19). This shaft is journaled 9 directly on balls 233 in a sleeve 234 that'is' secured by screws 235 to the bracket I58.

The shaft 232 has a bevel gear 249 at its inner end which forms on of the side gears of a differential that is designated as a whole at 244. The other side of this difierential is denoted at 252 designates the planetary pinion of the differential. This meshes with the two side gears 2 1?? and Edi. This pinion is journaled directly through balls 2:33 on a spider member 245 that is secured by a key and by a set-screw 266 to a shaft 2%. This shaft is journaled on balls 2% in shaft 232 and on balls 258 in side gear 2t! and on balls 25% in the bracket !53.

Integral with the side gear 2t 5' is a bevel gear 255. This gear meshes with a bevel gear (Figs. 5 and 19) that is integral with a shaft 257. This shaft is journaled on anti-friction bearings 258 and 259 in a swivel member 25% that is rotatably adjustable in the top of the cradle hou ing 3i. Secured to the upper end of this shaft 25'! is a bevel gear 262. This bevel gear meshes with a bevel gear 254 which is keyed to a sleeve 2556 which in turn is keyed to one end of a telescoping shaft 255. is journaled on anti-friction bearings 26? and in the swivel member 268.

opposite end 2&5 (Figs. 17, 18 and 19) of the tele coping shaft is keyed to a sleeve 2'50 which is iournaled on anti-friction bearings 21! and 2'52 in a swivel member 2M. This swivel is seu e l b g o an s e s 2' 5 to a ring Z'i'l, which, in turn, is secured by screws 2'58 to the top of the work head column 23. of the machine. a bevel gear 23! which meshes with a bevel gear 282 that is secured to a vertical shaft 28%. This shaft is journaled at its upper end on anti-friction bearings 235 in swivel member El i. At its lower end it has telescoping keyed engagement with a sleeve 28? that is journaled on anti-friction bearings 263 and 288 in the work head 3!?) of the machine.

Integral with the sleeve 28? is a bevel gear 2%. 29! that is keyed to a horizontal shaft 29 This shaft is journaled in a sleeve 2% which is secured by screws to work head 355. There is a spur gear 293 keyed to the outer end of the shaft 2&2. This spur gear meshes with a spur gear 223 that is secured to a stub-shaft 295 which is mounted in a uadrant There is another spur gear secured to this stub-shaft which I! J i meshes with a spur ear 293 that ha snlined connection with a s aft The shaft Si? is journaled on anti-i cticn bearings 38% and 392 in a sleeve that is secured by screws 385 to the work head 3E5. is a hypoid pinion till integral with the shaft at its inner end. meshes with a hypoid gear tilt which is secured by screws 339 (Fig. 18) to the work spindie i? of the machine.

The work spindle journaled on anti-friction bearings iii and 352 in the work head 315.

The work head is mounted inthe column f 1" vertical sliding movement on plane surfaced ways and Eli. Vertical adjustment of the work head be effected by rotation of the knurled which has a graduated dial sac 321i secured to it. knob is secured to or The sleeve 2% Fastened to the sleeve 2'52! is a This bevel gear meshes with a bevel gear 10 cutting spiral bevel gears, or of positioning the work axis above or below the cradle axis for cutting hypoid pinions.

Through the gearing described the work is driven in time with the cradle to effect the generating operation. The gears 225, 225, 230 and 23I are change gears and govern the ratio of the generating roll. The gears 293, 2%, 291, and 298 are change gears and govern the number of teeth to be cut in the work. The use of hypoid gears 3.8 and I96 and 301 and 308 for driving cradle and work spindle permits of fast speed operationoi both the cradle and work gear trains, minimizing the elfect of any possible errors in the gears of either of these trains on the work produced, a very important item in these days when gear-s must be cut to accuracies measured in thousandths of an inch.

The gear G (Fig. 1), which is to be cut, may be secured to the work spindle 3 lil by any suitable chucking mechanism. This chucking mechanism may be actuated by a draw bar 325 which is secured by nuts 326 to a sleeve 32? that is threaded into a piston 323. The piston is adapted to reciprocate in a cylinder which is designated as a whole at 3.38. The draw bar 3225 may be moved rearwardly to chucking position and forwardly to dechucking position by fluid-pressure or it may be moved rearwardly to chucking position by coil springs such as denoted at 532 and forwardly to released position by fluid-pressure. type of chucking mechanism is well known in the art and need not further be described.

During operation of the machine, the work is fed into operative relation with the cutter and then cutter and-work are rolled together to generate a tooth surface or a pair of tooth surfaces of the work, and then the cutter is withdrawn from engagement with the work and the work is indexed. The mechanism for moving the work toward and from operative position is actuated by rotation of barrel cam I50. The cam is provided with twofeed-track-ways l5! and I52 (Fig. 5), already mentioned. One of these track-ways controls the feed and withdrawal motions during a rough-cutting operation and the other trackway controls the .feed and withdrawal motions during a finish-cutting operation. The two cam rollers 34! and 2342 are adapted to be engaged selectively with the cam tracks i5l and I52 depending upon Whether a rough-cutting or a finish-cutting operation is to be performed. The two rollers 3 and 342 are journaled on posts 363 and 344, respectively, which are mounted for axial reciprocation in a cam lever 3&5 (Figs. 5 and .15). Racks 346 and 3M are cut into opposed faces of the posts 344 and 343, respectively. A spur pinion M8 is interposed between and meshes with the two racks. This spur pinion is integral with a shaft 13 39 which is iournaled in thecam lever 3 and .is manually rotatable to move one or the other roller 34'! or M2 selectively into engagement with the tracks liii and 5 2 of the cam. When one roller is in operative position, the other is retracted therefrom.

The lever 3 is pivotally mounted by means of a stud or pin 350, which is integral with it, in the cam housing I65. A gib 352, which is secured by screws 35.3 to the bracket, serves to hold and guide the lever in its pivotal movement.

Slidably mounted in an elongated slot 355 in the lever is a "block 356.. This blockis adjusted by means of a screw shaft 351 which is journaled in theleverjand whichthreads :into a nut 35% that thereof.

' is secured in the block 359. There is a pivot pin 359 integral with block 356 and on this pin there is pivotally mounted another block 359 which engages in an elongated slot 36| formed in an extension 392 of a cylinder 363. The cylinder is slidably mounted in aligned bearings or guides 364 and 395 (Fig. 16) of bracket 158. A piston 35'! is mounted to reciprocate in the cylinder 393. Integral with this piston is a piston rod 368. This piston rod is connected by a coupling pin 399 with a bar 319. The coupling pin 359 carries rollers 356 that engage in a recess 3' in bar 319. Bar 319 is connected to a sliding base 925 (Fig. 2) which slides on ways AM and 432 of sub-base 32 of the machine, as will be described more particularly hereinafter.

Fluid under pressure may be admitted to opposite sides of the piston 36'! to move the sliding base away from the cutter sufficiently to permit removal of a completed gear and positioning of a new work piece, but during cutting of a gear the piston 33'! is held in the position shown in Fig. 16 under fluid pressure and alternate feed and withdrawal of the work are controlled by cam I59 through whichever of its feed tracks I5! or l52 is in operation. Movement of the sliding base to loading position and its return to operative position are controlled by a valve (not shown) which may be operated by a lever 312 (Fig. 3).

The feed and withdrawal mechanism of the machine is similar in many respects to the mechanism disclosed in Carlsen Patent No. 2,302,004, granted November 17, 1942.

As previously stated, the work is indexed. periodically. The indexing mechanism may be of any suitable character. That shown is of the type disclosed in the pending application of Ernest Wildhaber, Serial No. 792,570, filed December 18, 1947, now U. S. Patent No. 2,477,105, granted July 26, 1949, and reference may be had to that application for a more complete description The indexing mechanism is actuated from the bevel gear 219 (Figs. 7, 8, and 19). This gear meshes with and drives not only bevel gear 2!! but also a bevel gear 375. This is indicated diagrammatically in Fig. 19, the gear 2l9 being shown in full lines in engagement with gear 2| l and in dotted lines in engagement with gear 375. The gear 315 is keyed at one end of a shaft 316. This shaft is suitably journaled in a bracket 371. Integral with this shaft is a cylindrical pinion 399 which meshes with a hypoid face gear 38L This gear is secured by screws 382 (Fig. 13) to a sleeve 399. The sleeve 384 has face clutch teeth formed on its outer end that are adapted to be engaged by face clutch teeth formed on the opposed face of a ring 393. The clutch is adapted to be held in engaged position by a nut 393 that threads onto a sleeve 389. The ring 383 is keyed to this sleeve 399. A coil spring 394, which surrounds sleeve 399 and seats against ring 383, tends to release the clutch. Sleeve 389 is keyed to a shaft 385. This shaft is journaled on antifriction bearings 396 and 381 in the bracket I58.

Keyed to the shaft 335 are a cam member 399 and an actuating plate 39f. Secured to the actuating plate 39! by screws 392 (Fig. 8) and the dowel pin 393 (Fig. 9) is a spur gear segment 395 and journaled on this segment is a roller 396. The roller is held on the segment by a plate 397 and screw 399. The roller is adapted to engage successively in cam slots 499 and AM formed in 2. Geneva plate 492. This Geneva; plate is keyed to shaft 298 (Figs. 8, l3 and 19). Keyed to this shaft, also, and positioned within a reces formed in one face of the Geneva plate is a segmental spur gear 999 which has teeth 995 at diametrically opposite sides of its axis registering with the slots 999 and 49 I, respectively.

The Geneva plate 2-92 is held against rotation during cutting by a lock dog 99? (Figs. 7, 8 and 12) which engages in a notch in the plate and which is secured to a lever 399 that is keyed to a shaft M9. This shaft is journaled in the bracket I58.

The cam 399 has two trackways 323 and 429 (Fig. 10). The lever 499 is held in locking position by action of a double-armed lever A H which is also keyed to shaft 919. One arm of this lever carries a roller 919 that rides on one trackway 423 of the cam. The other arm of this lever has a spring 315 housed in it which seats against an arm H8. The arm M8 is mounted rotatably on the hub of lever 9W. It carries a roller 919 that rides on the trackway 923 of cam 399. This roller is secured to arm M8 by a bolt 912 and nut 413. A pin 495, which threads into arm 418 (Fig. 12), and a nut 998, which threads onto the pin, serve to limit relative movement of arm 418 and lever 499.

Each of the cam tracks 923 and 924 has a dwell portion of large radius and a dwell portion of small radius, connected by rises, but the major and minor diametral portions of the two cams are slightly spaced angularly relative to one another in accordance with the angular spacing of rollers M5 and 359 so that the portion of one trackway which is of major radius is in alignment with the portion of the other trackway which is of minor radius and vice versa. When the locking dog 999 is in engaging position roller M9 is on the high part of cam surface 923 and roller M9 is on the low part of cam surface 423. The shaft 385 rotates continuously and makes one revolution per cycle of the machine and the cam 399 and actuating plate 39! revolve with it. When the roller 919 rides down off the high part of the cam surface 929 and the roller H9 rides up on the high part of cam surface 923, the lever 499 is swung outwardly to disengage dog 491' from Geneva plate 992. When this occurs, the actuating plate 39: is free to rotate under actuation of the gearing 2 l3-2 I 5. The result is that the roller 395 engages in one of the slot 999 or 99! which is then in registry with the roller and the actuating plate 39E drives the Geneva plate 492. The first part of themotion is under control of the roller 399. Thus, it starts slowly and accelerates gradually. When the two plates 39] and 492 have rotated far enough to bring segmental gear 395 into engagement with teeth of segmental gear 495, the motion is continued but at a uniform rate under control of said gearing. When the gears 395 and 999 rotate out of engagement, then the roller 395 again take control to complete the motion and bring the Geneva plate to a slow stop. As the Geneva plate 992 rotates, an increment of motion is imparted to the shaft 249 which operates through the differential 294 to add or subtract motion from the shaft 232 which drives the work spindle. Thus, indexing of the work spindle is effected. The Geneva plate makes half a revolution during indexing and then is locked up again.

The column 289 (Figs. 1, 2 and 17) which carries work head 3l5, is mounted upon a swinging base 429 for rectilinear adjustment thereon in the direction of the axis of the work spindle along ways 42! and 322 (Fig. 2). It is adapted to 

